Hanna Instruments Waterproof Combo pH / ORP / Temperature Pocket Tester (HI98121)

Hanna Instruments Waterproof Combo pH / ORP / Temperature Pocket Tester

The HI98121 is a professional-grade, waterproof pocket tester that simultaneously measures pH, ORP (redox potential), and temperature in a single compact device. Designed for pool technicians and water treatment professionals, it delivers fast, reliable readings for chlorine monitoring, water balance checks, and sanitation verification. The unit is buoyant and fully sealed against moisture, so accidental drops into pool water are never a disaster.

Key features

The HI98121 combines three critical water quality parameters in one ergonomic handheld instrument. It offers 0.01 pH resolution with ±0.05 pH accuracy and an ORP range of ±1000 mV with ±2 mV accuracy — more than enough precision for professional pool and spa management. Automatic Temperature Compensation (ATC) ensures pH readings remain accurate across varying water temperatures, while the continuously displayed temperature readout keeps you informed at a glance. The tester complies with the UNE-ISO 17381:2012 standard and switches off automatically after 8 minutes of non-use to conserve power.

Replaceable pH electrode

The included HI73127 pH electrode is a replaceable cartridge electrode. The electrode features a renewable fiber junction that can be extended slightly to eliminate blockages and restore response time, extending the working life of each electrode. Replacement requires only the electrode key supplied in the box, making field servicing quick.

Calibration & what’s included

The HI98121 supports automatic one- or two-point pH calibration using two sets of standard buffers (pH 4.01 / 7.01 / 10.01 or pH 4.01 / 6.86 / 9.18), with automatic buffer recognition for speed and confidence. The ORP sensor is factory calibrated and fixed, requiring no user calibration. The tester ships complete with the HI73127 replaceable pH electrode, protective cap, electrode replacement key, four 1.5 V batteries (approximately 250 hours of continuous use), and instruction manual.